4 Night Crossover Event Begins with Supergirl 28 November! + NEW POSTER! Nov 23, 2016 | It’s Heroes v Aliens on #DCWeek! The 4 night crossover event begins with #Supergirl Monday, November 28 at 8/7c on The CW. Here’s the new poster released that featured Supergirl Watch Previews Related posts: TONIGHT! Supergirl Season 2 Begins! New Legends of Tomorrow Crossover with Melissa as Supergirl! Entertainment Weekly Nov 18 2016 Epic Crossover Scans TV Insider Interviews Melissa Benoist About Supergirl Season 1 New CW Supergirl Trailer!